LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Discussion about displays and related hardware including MiSTer filters and video settings.
sofakng
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LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Unread post by sofakng »

I'm testing a new monitor with MiSTer but I can't seem to display 2560x1440 or 1920x1440. However, according to the manual it should be supported:

Screenshot 2022-09-07 145109.png
Screenshot 2022-09-07 145109.png (54.48 KiB) Viewed 771 times

I've tried the following modeline but it doesn't produce an image:

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video_mode=2560,48,32,80,1440,2,4,38,183000,+hsync,-vsync

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Send HDMI parameters:
video: 2560(2560), 48(48), 32(32), 80(80), 1440(1440), 2(2), 4(4), 38(38), +hsync, -vsync
PLL: 0x4, 0x707, 0x3, 0x10000, 0x5, 0x202, 0x9, 0x2, 0x8, 0x7, 0x7, 0xA3D70A3D, Fpix=183.000000
I've also tried many other modelines but nothing works:

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video_mode=12
video_mode=14
video_mode=1920,128,208,344,1440,1,3,56,234000
video_mode=1920,128,208,344,1440,1,3,56,234000,+hsync
Does anybody have any ideas?
Malor
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Re: LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Unread post by Malor »

The DE-10 board is normally limited to 1080p. Going above that is tricky and involves overclocking the scaler chip and repeating pixels.

I have the one-generation-older monitor than yours, the GN850, and I just run 1080p.

You can probably get to higher resolutions, but it will likely be a pain. Hopefully folks that know more than I do will chip in on how to do it.
sofakng
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Re: LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Unread post by sofakng »

Have you tried the 1440p and other non-standard resolutions?

According to another user it works fine on that monitor? (34GN850)
zakk4223 wrote: Fri Apr 02, 2021 3:28 am I have that monitor. Works great, displays all the weird console/arcade/etc refresh rates
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Re: LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Unread post by AmanoJacu »

See this thread:

viewtopic.php?t=4558

I have 2 similar LG monitors, in one of them the Mister works in 1920x1440, in the other not. I still haven't tried the 2560x1440 pixel doubling new mode in the one that doesn't work (32GK850G), it works fine in the other one (32GK850F) for supported cores.

From the info I gathered, it looks the monitors with g-sync instead of free-sync are the ones with trouble in this mode.
sofakng
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Re: LG 34GN950 - Not working with any 1440p resolution? (re: manual says its supported?)

Unread post by sofakng »

Thanks so much. I'm not sure why I didn't see that thread when I was searching.

It definitely looks like a G-Sync issue. I also have the new Alienware A3423DW (QD-OLED) and it accepts 2560x1440 but not 1920x1440 or the other odd resolutions.

(I'm looking for a new ultrawide to replace my older Acer X34 so I've been comparing the Alienware and the LG 34GP850)
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